The large-scale production of waste materials, primarily in industrialized countries, has led to major ecological and economic problems on a worldwide scale. Waste materials, which may be defined as undesired substances that result from the production or use of a desirable, useful material, are of three main types: household, industrial and toxic or hazardous waste.
In the absence of efficient waste recycling plants, very large amounts of waste materials are deposited in landfill sites, which entails high cost, both to the environment and to the economy. In addition to the problems arising from pollution, fire and explosion risk, an additional concern is the loss of potentially valuable raw materials which could otherwise be recycled for use as starting materials or intermediates for many manufacturing processes.
While many different recycling technologies have been developed, these are generally applicable only to single materials or a class of materials, and hence require sorting or pre-processing of the waste.
The problem is compounded when the waste material includes highly toxic, inflammable, and potentially explosive substances. The increasingly widespread use, and hence disposal, of electrical batteries provides an example of the generation of toxic waste from industrial and household sources. Electrical batteries are a source of chemical contamination, as a result of their toxic components such as cadmium, cobalt and nickel. In addition, they may pose a fire hazard and explosion risk as a consequence of components such as Lithium and other exothermic materials.
U.S. Pat. No. 4,637,928 discloses a method for treating articles such as batteries by opening the battery casings and contacting the interiors of said batteries with an alkaline agent.
Co-owned International patent application no. PCT/IL99/00045, incorporated herein by reference, discloses a recovery process for mixed waste, in which components such as metals are separated from each other as halides, following gaseous phase halogenation. Although this process is highly efficient, for certain applications the equipment required may be relatively expensive.
It is a purpose of the present invention to provide a highly efficient process for the recovery of metals from unsorted mixed waste, in particular from electrical batteries. It is a further purpose of the present invention to convert hazardous components present in the waste to non-hazardous materials.
It is another object of the present invention to provide a process that is ecologically clean, economically advantageous and industrially convenient.
It is a further object of the present invention to provide a process for rendering electrical batteries non-hazardous, while also permitting recovery of the valuable raw materials contained therein.
Other objects and advantages of the invention will become apparent as the description proceeds.